Why won't my Nikon D90 connect to my Mac Air?

I'm running Lion… It won't even show as connected on my desktop. Following instructions on manual… Camera off, plug in, camera on… Nothing. Any ideas?

Trade your computer for a PC? My old PC has no problem connecting to my D90…

OK, I know how fanatic you Apple types are. I would get a card reader and use it. If that doesn't work, I'd go online to Apple and research it there.